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1.
广州既是改革开放的前沿阵地,也是岭南文化的传播和发展中心。分析广州近年来在文化建设方面的实践经验,特别是在推动岭南文化、广府文化创造性转化和创新性发展方面的经验,对于进一步贯彻落实习近平总书记关于文化自信建设的重要论述精神,扎实推进文化建设具有重要作用。  相似文献   
2.
Recovering alcohols from dilute fermentation broth is an emergent task in bio-fuel production process. Since they are primary planned for fuels, energy required to separate these alcohols should be considered in evaluating the potential of a separation technology. A membrane-based process, pervaporation, is of special interest because of its environmental friendliness and easy integrating character. This review probes into the fundamentals of pervaporation especially in terms of the heat required for evaporation. Meanwhile, the separation data of the most representative alcohol-selective pervaporation membranes reported in the literatures are collected and compared with the vapor–liquid equilibrium curve, which represents the distillation selectivity. They include:inorganic membranes, silicon rubber based membranes, Mixed Matrix Membranes and some other special materials. By doing so, the status of alcohol recovery via pervaporation would be more clear for researchers.For ethanol recovery, it is selectivity rather than flux that is in urgent need of solution. While for butanol recovery,membranes with satisfactory selectivity have been developed, increasing the separation capacity would be more pressing.  相似文献   
3.
The traditional gas purification techniques such as wet gas desulfurization, with their advantages of large-scale implementation and maturity, have still been widely used. However, the main drawback of these techniques is the low transfer efficiency, which normally needs towers as tall as tens of meters to remove the pollutants. Therefore, new technologies which could enhance the mass transfer efficiency and are less energy-intensive are highly desirable. As a process intensification technology, high-gravity technology, which is carried out in a rotating packed bed(RPB), has recently demonstrated great potential for industrial applications due to its high mass transfer efficiency, energy-saving, and smaller volume. This consequently provides higher efficiency in toxic gas removal, and can significantly reduce the investment and operation costs. In this review, the mechanism,characteristics, recent developments, and the industry applications of high-gravity technologies in gas purifications, such as hydrogen sulfide, nitrogen oxide, carbon dioxide, sulfur dioxide, volatile organic compounds and nanoparticle removal are discussed, most of the demonstration projects and practical application examples in gas purification come from China. The perspective and prospective of this technology in gas purification and other fields are also briefly discussed.  相似文献   
4.
In this work, the effects of support surface pore structures(including surface pore size, surface pore density and surface porosity) on the performance of thin film composite(TFC) gas separation membrane over a wide pressure range(from 0.3 to 2.0 MPa) were studied. To fulfill it, the polysulfone(PSf) supports with different surface pore structures were prepared. Two kinds of wide-accepted polymeric membrane materials, i.e., polyvinylamine(PVAm) and Pebax 1657 copolymer, were used as skin layer materials. We pointed out for the first time that the support surface average pore size and pore density could affect the chain mobility of polymer of skin layer at the support surface pore entrance, then, can affect the TFC membrane performance. Besides, we also discussed the effects of support on the TFC membrane performance when the feed pressure changes for the first time. This work can provide guidance for choosing a suitable support for TFC gas separation membrane.  相似文献   
5.
Fossil fuel combustion is one of the major means to meet the mounting global energy demand. However, the increasing NOx and N2O emissions arising from fossil fuel combustion process have hazardous effects. Thus, mitigating these gases is vital to attain a sustainable environment. Interestingly, oxy-fuel combustion in fluidized bed for carbon capture and minimized NOx emissions is strongly sustainable compare to the other approaches. It was assessed that NOx formation and fuel-N conversion have significant limitation under oxy-fluidized bed compared to air mode and the mechanism of NOx formation is still deficient and requires further development. In addition, this review paper discussed the potential of primary measure as low emission process with others supplementary techniques for feasible NOx reduction. The influences of combustion mode, operating parameters, and reduction techniques such as flue gas recirculation, oxygen staging, biomass co-firing, catalyst, influence of fluidized bed design and structure, decoupling combustion and their merges are respectively evaluated. Findings show that significant minimization of NOx emission can be achieved through combination of primary and secondary reduction techniques.  相似文献   
6.
土木工程施工课程作为土木工程及工程管理专业的学科基础课和核心专业课程,在疫情防控期间"停课不停教""停课不停学"的要求下,通过线上平台进行授课。由于土木工程施工课程内容庞杂、综合性强、实践性强,且章节之间关联性较弱,探究既能使学生快速适应,又能保证教学质量的在线教学方法至关重要。以华南某高校土木工程施工课程为例,基于中国大学MOOC、建筑云课、腾讯课堂、QQ群等线上平台讲授教学内容,并运用问卷调查对课程线上教学效果进行评价。结果表明,线上教学为学生提供了丰富灵活的学习方式,显著提高了学生的自主学习能力,扩大了学生的知识面,达到了较好的学习效果。  相似文献   
7.
丁力扬 《建筑师》2022,(6):113-118
本文回顾了2022 年1月底至6 月初在宾夕法尼亚大学费舍尔美术图书馆和建筑档案馆举办的“中国建造: 现代建筑百年对话”展览。旨在呈现展览的原貌,本文概述了展览的背景和缘起,介绍了展览的具体内容和策 展思路,并回顾了展览进行过程中和结束后来自各界的反响和评价。本文将“中国建造”展置于近二十年来一 系列有关宾夕法尼亚大学与中国现代建筑关系的学术活动的框架内,强调其目标是在立足于“第一代“中国建 筑师与宾夕法尼亚大学布扎体系首次交集的一个世纪之后,审视现代建筑发展进程中的跨文化对话,揭示中国 建筑实践中的跨世纪连贯性,并对全球性建筑技术的探索和设计创作中本土身份之间的关系进行进一步地诠 释。文章指出本次展览是对中西现代建筑“百年对话”主题的一次有意义的深入扩展性研究,并提出了中西建 筑文化交流这一宏观话题进一步研究的可能方向。  相似文献   
8.
Thiamine Deficiency Complex (TDC) is an ongoing problem impacting salmonine health in various waterbodies, including Lake Ontario. The prevalence of TDC has been variable and explanations for differences are limited. In the current study, thiamine concentrations were measured in eggs, liver tissue, and muscle tissue sampled from brown trout (Salmo trutta), Chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), lake trout (Salvelinus namaycush), and steelhead trout (O. mykiss) that were collected from Lake Ontario and its surrounding tributaries. The occurrence of TDC was measured for each species based on TDC-induced offspring mortality rates under laboratory conditions. TDC-induced offspring mortality was observed for all species except brown trout. For affected species, egg free thiamine (Th) was consistently low compared to lake trout collected from Lake Superior that are considered thiamine replete. In addition, species with the lowest percentages of Th in their eggs were the most susceptible to TDC, suggesting that limited thiamine reserves in the form of Th may cause TDC-induced offspring mortality. Lastly, our results show that egg thiamine concentrations have yearly variation and increased for all species throughout the study. Reasons for such variation are undetermined; but, if egg thiamine concentrations continue to increase, the impacts of TDC on these salmonine species may lessen. Future monitoring is needed for determining if thiamine concentrations are increasing and the potential impacts that may have on the entire Lake Ontario fishery.  相似文献   
9.
Perovskite oxides LaCoO_3 prepared by templating, co-precipitation and sol-gel method with different complexants were systematically characterized and its catalytic performances for CO oxidation were investigated. The samples were characterized by X-ray diffraction, thermogravimetry analysis and differential scanning calorimetry, N_2 physisorption, transmission electron microscopy, temperature program reduction of hydrogen, temperature program desorption of oxygen and X-ray photoelectron spectroscopy measurement, results of which show that the properties of LaCoO_3, such as surface morphology, surface area, surface compositions, redox capability, oxygen vacancy, as well as the calcination temperature and formation mechanism, depend intimately on the preparation method. Catalytic tests indicate that the sample prepared by carbon templating method shows the best activity for CO oxidation, with full CO conversion obtained at 135 ℃. In particular, the catalyst can be activated and significant increase of activity can be obtained with the increase of reaction time. The cyclic and longterm stability of catalysts were discussed and compared.  相似文献   
10.
Two kinds of Cu-Al_2O_3 composites(with and without La) were prepared via mechanical alloying-spark plasma sintering(MA-SPS) method. Microstructure, mechanical properties and electrical resistivity were investigated systematically using metallography, scanning electron microscopy, transmission electron microscopy, mechanical and electrical properties testing. The results indicate that an appropriate amount of La can homogenize the distribution of Al_2O_3. As such, yield strength, ultimate tensile strength and elongation of Cu-Al_2O_3-La are greatly increased. Some semi-coherent interface between Cu and Al_2O_3 is found, which means a low interface energy. The grain shape of Cu changes to irregular band with the addition of La. This change results in a density decrease of grain boundary and reduces electrical resistance. Lanthanum may exist in the form of La_2O_3.  相似文献   
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